Understanding representation geometry logic
This topic applies to ArcEditor and ArcInfo only.
Since geometric effects alter geometry and even, in some cases, geometry type, it is important to ensure that representation rules maintain geometric logic. Geometric effects operate sequentially. The output of one geometric effect becomes the input of the following one, so you can use a chain of geometric effects to achieve the appropriate geometry logic. Regardless of how the geometry is dynamically changed through the chain of geometric effects, the final output of the last effect must match the geometry type of the symbol layer. If a warning symbol appears on the heading of the symbol layer, there is a disconnect in the geometry logic. The symbol layer you just added doesn't have any geometry to symbolize.
Polygon geometry |
Line geometry |
Point geometry | |
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Fill symbol layer |
Symbolizes polygon interior |
Produces geometry logic error because there is no polygon geometry to fill |
Produces geometry logic error because there is no polygon geometry to fill |
Line symbol layer |
Symbolizes polygon outline |
Symbolizes lines |
Produces geometry logic error because there is no line geometry to draw |
Marker symbol layer |
Places markers in polygons with a marker placement style |
Places markers on lines with a marker placement style |
Places markers on points with a marker placement style |
For example, adding a fill layer to a line representation rule would generate a warning because there is no polygon geometry to fill. To repair the logic, add a line-to-polygon geometric effect to either the fill layer or the global effects portion of the rule. However, the opposite scenario—adding a line symbol layer to a polygon representation rule—would not generate a warning, because the line symbol layer will symbolize the outlines of the polygon geometry.
To change input geometry |
To output geometry |
Use |
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Point |
Point |
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Point |
Line |
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Point |
Polygon |
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Line |
Point |
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Line |
Line |
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Line |
Polygon |
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Polygon |
Point |
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Polygon |
Line |
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Polygon |
Polygon |
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